Glaucoma is a leading cause of blindness in the United States and worldwide. Technologies to aid in the diagnosis and monitoring of glaucoma are of critical importance because the disease may develop and progress unnoticed until severe damage has developed, and this damage is then irreversible. Optical coherence tomography (OCT) is a relatively new technology which permits visualization and precise measurement of the retinal layers in the living eye, including the retinal nerve fiber layer and the ganglion cell layer that are damaged by glaucoma. Thus, the primary goal of the NIH supported Advanced Imaging for Glaucoma (www.AIGstudy.net) is to improve the early detection and long-term monitoring of glaucoma by advancing the technology of optical coherence tomography (OCT). One of the major discoveries of the AIG project was the finding that measurement of retinal blood flow using new Doppler OCT technology provided a potential new way of measuring the severity of glaucoma and for assessing which individuals may be at risk for further progression. The excitement from this initial discovery generated interest from many glaucoma specialists around the country including the clinical centers within the AIG group. For Doppler OCT based retinal blood measurement to become an important clinical tool for caring for patients with glaucoma or suspected to have glaucoma, considerable additional data is required. For example, normal values and variability of retinal blood flow in a large group of individuals, and a better understanding of what other factors affect flow measurements in patients with and without glaucoma is of critical importance. At present until fully automatic software can be produced, rapidly generating accurate retinal blood flow measurements requires some input from trained expert humans in specialized image reading centers. The objective of this revision/supplement application is to support and expand such a center to generate the large amounts of Doppler OCT retinal blood data required to answer critical questions on how retinal blood flow can best be used to diagnose and monitor patients with glaucoma. In particular we will make progress towards establishing a normative database for retinal blood flow and identify which factors influence or affect blood flow measurements. We will also study the predictive value of blood measurements for glaucoma progression as well as the effect of glaucoma surgery on retinal blood blow. Given the high prevalence of glaucoma, the development of these approaches has the potential to make a significant impact on preventing visual loss in the United States and worldwide. PUBLIC HEALTH RELEVANCE: Development of new strategies, such as Doppler OCT-derived retinal blood flow measurements, may allow for earlier and more reliable detection of glaucoma, and more precise and careful monitoring of the disease. Blood flow measurements may also provide new insights into the pathogenesis of glaucoma, which could lead to improved strategies for prevention and treatment. Given that glaucoma is a major cause of blindness in the United States, this research could have considerable public health benefit.